Mercaptotetrazaindene in photographic printing plate development

ABSTRACT

A PROCESS FOR DEVELOPING A SILVER HALIDE PHOTOGRAPHIC ELEMENT WHICH COMPRISES DEVELOPING A LITHOGRAPHIC LIGHTSENSITIVE MATERIAL IN THE PRESENCE OF THE COMPOUND REPRESENTED BY THE FOLLOWING GENERAL FORMULA,   2-R1,5-R4,6-R3,7-R2-2H-IMIDAZO(4,5-B)PYRIDINE   WHEREIN R1 AND R2 WHICH MAY BE THE SAME OF DIFFERENT, REPRESENT A HYDROGEN ATOM, A HYDROXYL GROUP, AHYDROCARBON GROUP OR -SR5; AT LEAST ONE OF SAID R1 AND R2 BEING -SR5; R5 REPRESENT A HYDROGEN ATOM OR ALKYL RADICAL; AND R3 AND R4, WHICH MAY BE THE SAME OR DIFFERENT, REPRESENT A HYDROGEN ATOM, A HYDROXYL GROUP A HALOGEN ATOM, OR A HYDROCARBON GROUP; SAID R3 AND R4 MAY BE RING-CLOSED TO FORM A 5- OR 6 MEMBERED RING.

3,782,945 MERCAPTOTETRAZAINDENE IN PHOTOGRAPHIC PRINTING PLATE DEVELOPMENT Isao Shimamura, You Iijima, Eiichi Okutsu, Haruhiko Iwano, Tadao Shishido, and Reiichi Ohi, Kanagawa, Japan, assignors to Fuji Photo Film Co., Ltd., Minami Ashigara-shi, Kanagawa, Japan No Drawing. Filed June 11, 1971, Ser. No. 152,397 Claims priority, application Japan, June 11, 1970, 45/ 50,564 Int. Cl. G03c 5/30 US. Cl. 96-663 19 Claims ABSTRACT OF THE DISCLOSURE A process for developing a silver halide photographic element which comprises developing a lithographic lightsensitive material in the presence of the compound represented by the following general formula,

wherein R and R which may be the same or different, represent a hydrogen atom, a hydroxyl group, a hydrocarbon group or -SR,-,; at least one of said R and R being -SR R represents a hydrogen atom or an alkyl radical; and R and R,, which may be the same or different, represent a hydrogen atom, a hydroxyl group, a halogen atom, or a hydrocarbon group; said R and R may be ring-closed to form a 5- or 6-membered ring.

BACKGROUND OF THE INVENTION (1) Field of the invention The present invention relates to a process for developing a silver halide photographic element for printing plate and more particularly the invention relates to a developing process having a wide developing latitude and giving images having good quality.

(2) Description of the prior art Preparation of a photographic master for printing is generally carried out by reproducing a dot image or line image on a lith-type light-sensitive material or a high contrast light-sensitive material having an excellent image sharpness. Such lith-type light-sensitive materials include a lith plate (lithographic plate) or lith film (lithographic film). The original picture consisting of a continuous tone image is recorded on these materials with a continuous regularly distributed crowd of dots, namely, the continuous tone image is converted to a divided discontinuous dot image. In this process the density variation of the original is changed to a dot size variation. The other group of lithographic materials include lith line plate (lithographic line dry plate) or lith line film (lithographic line film) for recording line image.

In the former case, division into a network of dots is carried out by the use of a glass cross-line screen or contact screen. The original is printed on a lith material through such screen, followed by development to produce a dot image. The quality of printed materials depends on dot quality. The excellent dot image should United States Patent 0 ice quite difiicult to avoid it completely since even a high contrast photographic material has an intermediate density. In the case of a line image, which may be regarded as a connected series of dot images, such inter-. mediate density zone is also not desired.

Furthermore, at the development of such photographic silver halide element for printing plates (hereinafter referred to as photographic plates for prinitng), the control of the developing period of time is an important problem. In general, a photographic plate for printing has a feature that the latitude of the developing time thereof for obtaining the optimum dot qualities is quite narrow. Particularly, if a developing period of time is prolonged, the qualities of dots are degraded. It is an important theme in the development of the photographic plate for printing to overcome such difiiculties and widen the latitude of the optimum developing time.

An object of this invention is to provide a developing process for lithographic materials, which can reduce fringe and can improve latitude of development.

SUMMARY OF THE INVENTION As the results of various investigations, the inventors have found that the above object of this invention can be attained by conducting the development of the photographic plate for printing in the presence of the tetraazaindene compound represented by the following general formula:

N N RFC i Ila-43 I //G RI wherein R and R which may be the same or different, represent a hydrogen atom, a hydroxyl group, a hydrocarbon group or -SR at least one of said R and R being SR R represents a hydrogen atom or an alkyl group, and R and R.,, which may be the same or different,

Compound 1: l,3,3a,7-tetraazaindene-i-thiol.

Compound 2: fi-methyl-l,3,3a,7-tetraazaindene-4-thiol.

N N HaC C C HG I l Compound 3: 6-t-butyl-l,3,3a,7-tetraazaindenei-thiol.

I SH

I s H Compound 5: fi-nonyl-l,3,3a,7-tetraazaindonc-4-thio1.

I SH

Compound 6: G-undecyl-l,3,3a,7-tetraazatndeno-4'thiol.

I SH

Compound 7: 6-heptadecyl-l,3,3a,7-tetraazindene-4-thiol.

N N -CnHar-C C 11(3 I I CH I SH Compound 8: fi-phcnyl-l,3,3a,7-tetraazaindene-4-thiol.

I SH

Compound 10: 2, fi-dlmethyl-l, 3, 3a, 7-tctraazulndoneA-thlol.

I SH

C-CH;

Compound 11: fi-ethyLfi-methyl-l, 3, 3a, 7-tetraazaindene-4-thio].

I SH

Compound 12: fi-iso-butyl-G-mothyl-l, 3, 3a, 7-tetraazaindene-4thiol1 I SH Compound 13: 2-benzyl-6-methyl-l, 3, 3a, 7-tetraazaindenet-thiol.

Compound 14: 2-mcthyltl1io-4-hydroxy-61nothyl-1,3,3a,7-totraazaindeno.

HsCC C HA3 III CS-CH;

('3 N CH Compound 15: 4, 6-dlhydroxy-2-methylthio-l, 3, 3a, 7-totraazaindcno.

HO-C C C-S-CHa HC\ /N\ C) N OH Compound 16: 4-hydroxy-2-1nethylthio-fi, 6-trimethy1cno-1, 3, 3a, 7 -totraazaindene.

C O H2O (I) III CS CH3 s CH2 (3 N Compound 17: 4-hyd1oxy-2-methylthio-5,G-tetramethylene-l,3.3a,7-

tetraazaindene.

fig

H20 C C I I C S CH3 H20 0 I OH DETAILED DESCRIPTION OF THE INVENTION The Compounds 1-8 may be prepared by reacting 3-amino-1,2,4-triazole with corresponding acylacetic acid esters, followed by chlorination of the products by phosphorus oxychloride then reacting the products with thiourea.

The Compound 9 may be obtained by bromination of the Compound 2 in acetic acid.

The Compounds 14-17 may be obtained by the coudensation reaction of 3-amino-5-methylthio-1,2,4-triazole and corresponding ketoesters or diethyl malonate (Compound 15).

The amount of the compound used in this invention is varied according to the composition of the developing solution and the nature of the emulsion to be employed, but in case of incorporating the compound in the developing solution, it is preferable that the amount of the compound b from 1 10- mol to 1 10- mol per liter of the developing solution, and in case of incorporating it in the silver halide emulsion, it is preferable that the amount of it be in a range of from 1 10 mol to 1 10 mol per mol of the silver halide.

The developing solution for lithographic materials ordinarily contains hydroquinone as a developing agent,

a small amount of a sulfite as preservatives, sodium carbonate, sodium hydroxide, boric acid, or acetic acid as a pH buqer, and other additives, such as an alkali bromide. The developing solution may sometimes contain a softener for hard water, an organic solvent, a polyalkylene oxide compound, ascorbic acid, etc.

The emulsion used for the photographic plate for printing is an ordinary silver halide photographic emulsion and a silver chloride emulsion, a silver bromide emulsion, a silver chlorobromide emulsion, a silver iodobromide emulsion, and a silver chloroiodobromide emulsion are employed, although the silver chlorobromide is particularly preferable. Such a silver halide emulsion is prepared by dispersing the silver halide in a medium, such as gelatin or a mixture of gelatin and a synthetic polymer. The silver halide emulsion may be sensitized chemically by ammonium thiosulfate, sodium thiosulfate, or allylthiourea; a gold compound, such as a complex salt of a monovalent gold and thiocyanic acid; or a combination of them. Moreover, the silver halide emulsion may be optically sensitized by adding thereto a spectral sensitizer such as a cyanine dye, merocyanine dye and the like. Also, the silver halide emulsion may contain a heterocyclic compound, such as benzotriazole or a polyalkylene oxide compound, an amine compound, and further may contain' a hardening agent such as formaldehyde or mucochloric acid. Furthermore, the silver halide emulsion may contain a surface active agent such as saponine for facilitating the coating operation.

In case of using the compound of this invention in the silver halide photographic emulsion, the compound may be incorporated in the silver halide emulsion at any stage during the preparation of the photographic emulsion, but the most preferable results are obtained by adding the compound at a stage after the postripening and before coating. The compound may be added as a solution thereof in an organic solvent, such as methanol, ethanol, acetone, etc. The compound may of course be incorporated directly in the silver halide emulsion but may be incorporated in an adjacent layer of the silver halide emulsion layer such as a protective layer to diifuse the compound into the silver halide emulsion layer from the protective layer.

The merits of this invention are practically shown by the following examples of this invention.

EXAMPLE 1 A commercially available lithographic film was exposed by a sensitometer using an optical wedge attached with a magenta contact screen of 150 lines and then developed for 2-5 minutes at 20 C. in the developing solution prepared from the two kinds of the concentrated liquids having the following formulas:

Developer 1 Liquid A:

Distilled water (50 C.) cc 50 Triethylene glycol cc 30 Formaldehyde-sodium bisulfite addition product g 45 Hydroquinone g 16 Distilled water to make 125 cc. Liquid B:

Distilled water (50 C.) cc 100 Sodium sulfite g 2 Sodium carbonate (monohydrate) g 30 Sodium hydroxide g 5 Boric acid g 5 Sodium bromide g 2 Distilled water to make 125 cc.

At the use of these liquids, the liquid A was first added to 750 cc. of water and then the liquid B was added to the mixture so that the whole volume of the final solution became 1,000 cc.

Developer 2 0.15 g. of the Compound 13 described above was added to the liquid A of the Developer 1. The composition of liquid B was the same as the liquid B of the Developer 1.

About the two kinds of samples developed by the two kinds of the developing solutions respectively, the widths of the fringes around the dots were measured by tracing the dots of 20% in dot area ratio by means of a microdensitometer.

On the other hand, the specific sensitivity expressed by the relative sensitivity when the exposure amount giving the dots of 50% in dot area ratio to the sample, by developing it in the Developer 1 for 3 minutes, was assumed to be 10, is shown in Table 1 together with the above results.

From the results shown in Table 1, it will be understood that when the developing solution prepared from Developer 2 containing the Compound 13 of this invention was used, the development proceeded more slowly than the case of using the Developer 1 and also the width of fringe when the period of the development was prolonged was smaller than the latter case. In other words, the developer containing the Compound 13 of this invention has a wider latitude for the dot qualities than the case of using the developer containing no compound of this invention.

EXAMPLE 2 A commercial lithographic film was exposed with a sensitometer through an optical wedge for sensitometry attached with a magenta contact screen of 150 lines and then developed for 2-5 minutes at 20 C. in the developer prepared by mixing the two kinds of the concentrated liquids having the following composition:

Developer 3 Liquid A:

Distilled water (50 C.) cc 50 Diethylene glycol cc 15 'Methyl Cellosolve cc 15 Formaldehyde-potassium bisulfite addition product g 45 Hydroquinone g 16 L-ascorbic acid g 1 Distilled water to make 125 cc.

Liquid B:

Distilled water (50 C.) cc Potassium sulfite g 2 Potassium carbonate g 40 Potassium hydroxide g 6 Glacial acetic acid cc 2 Potassium bromide ..g 2

Distilled water to make cc.

At the use of the developer, the liquid A was added to 750 cc. of water and then the liquid B was added to the mixture so that the whole volume of the resultant developer became 1,000 cc.

Developer 4 0.18 g. of the Compound 5 of this invention was added to the liquid A of the Developer 3.

The widths of the fringes around the dots of each of the two samples thus developed were measured by tracing the dots of 20% in dot area ratio by means of a microdensitometer.

On the other hand, the specific sensitivity expressed by the relative sensitivity when the exposure amount of giving the dots of 50% in dot area ratio to the sample by developing it in the Developer 3 for 3 minutes was assumed to be 10 is shown in Table 2 together with the above results.

From the results shown in Table 2, it will be understood that when the developer prepared from the Developer 4 containing the Compound 5 of this invention was used, the development proceeded more slowly than the case of using the Developer 1 and the width of the fringe when the period of development was prolonged was smaller than the latter, that is to say, the developer containing Compound 5 of this invention had a wider latitude for the dot qualities than the case of using the developer containing no such compound of this invention.

EXAMPLE 3 A commercially available lithographic film was used to take a photograph of an optical wedge for sensitometry through contact screen of 150 lines magenta and then developed for 2-5 minutes at 20 C. in the developer having the following composition:

Developer 5 Distilled water (30 C.) cc 800 Sodium carbonate(monohydrate) g 42 Formaldehyde-sodium bisulfite addition product g 60 Potassium bromide g 2 Hydroquinone g 18 Sodium sulfite g 2 Distilled water to make 1,000 cc.

Developer 6 10 ml. of a 0.2% methanol solution of the Compound 3 of this invention was added to the Developer 5.

The widths of the fringes around the dots of the samples thus developed were measured by tracing the dots of 20% in dot area ratio by means of microdensitometer.

On the other hand, the specific sensitivity expressed by the relative sensitivity when the exposure amount of giving the dots of 50% in dot area ratio to the sample, by developing it in the Developer 5 for 3 minutes, was assumed to be 10, is shown in Table 3 together with the above results.

TABLE 3 Developer 5 Developer 6 Developing time (min.) 2 3 4 5 2 3 4 5 Fringe width (micron). 17 12 16 29 17 12 14 19 Specific sensitivity 5 10 18 35 5 10 14 EXAMPLE 4 A commercially available lithographic film was used to take a photograph of an optical wedge for sensitometry through a magenta contact screen of 150 lines and then developed in the developer having the following composition for 25 minutes at 20 C.

8 Developer 7 Distilled water (30 C.) cc 800 Sodium carbonate (monohydrate) g 50 Formaldehyde-sodium bisulfite addition product g-- 45 Potassium bromide g 2 Hydroquinone g 18 Sodium sulfite g 2 Distilled water to make 1,000 cc.

Developer 8 10 ml. of a 1% methanol solution of the Compound 6 of this invention was added to the Developer 7.

The widths of the fringes around the dots of each sample were measured by tracing the dots of 20% in dot area ratio by means of a microdensitometer.

'On the other hand, the specific sensitivity expressed by the relative sensitivity when the exposure amount of giving the dots of 50% in dot area ratio to the sample, by developing it for 3 minutes in the Developer 7, was assumed to be 10, is shown in Table 4 together with the above results.

TABLE 4 Developer 7 Developer 8 Developing time (min) 2 3 4 5 2 3 4 5 Fringe width (micron) t 18 13 18 30 18 13 15 20 Specific sensitivity 5 10 19 37 5 10 15 24 To a silver chlorobromide gelatino emulsion containing 30 mol percent of silver bromide and sensitized by a merocyanine dye, the compound 15 of this invention was added in an amount of 0.3 lO- mol per mol of the silver halide. A light-sensitive material prepared by coating the silver halide emulsion on a su port was used to make a photograph of an optical wedge for sensitometry through a magenta contact screen of lines and then developed for 2-5 minutes at 20 C. in the Developer 1 shown in Example 1. For the sake of comparison, a comparison sample film was prepared by using the silver halide emulsion, same as above, except that the compound of this invention was not added, and processed by the same way as above. The results obtained are shown in Table 5.

TABLE 5 Comparison Sample of sample this invention Developing time (min Fringe width (micron Specific sensitivity an exposed lithographic light-sensitive material with a compound represented by the following general formula:

wherein R, and R which may be the same or diiferent, represent a hydrogen atom, a hydroxyl group, a hydrocarbon group or -SR at least one of said R and R being SR R represents a hydrogen atom or an alkyl radical; and R and R which may be the same or different, represent a hydrogen atom, a hydroxyl group, a halogen atom, or a hydrocarbon group; said R and R may be a ring-closed to form a 5- or 6membered ring, the developer employed during the development step containing as its essential components, hydroquinone, an aldehyde-alkali hydrogen sulfite addition product and a small amount of a sulfite material as a preservative.

2. The developing process as claimed in claim 1 wherein the amount of the compound incorporated in the developer is from 1 1O- mol to 1X10 mol per liter of said developer.

3. The process of claim 1, wherein said compound is 1,3,3a,7-tetraazaindene-4-thiol.

4. The process of claim 1, wherein said compound is 6-methyl-1,3,3a,7-tetraazaindene-4-thiol.

5. The process of claim 1, wherein said compound is 6-t-butyl-1,3,3a,7-tetraazaindene-4-thiol.

6. The process of claim 1, wherein said compound is 6-pentyl-1,3,3a,7-tetraazaindene-4-thiol.

7. The process of claim 1, wherein said compound is 6-nonyl-1,3,3a,7-tetraazaindene-4-thiol.

8. The process of claim 1, wherein said compound is 6-undecyl-1,3,3a,7-tetraaZaindene-4-thiol.

9. The process of claim 1, wherein said compound is 6-heptadecyl-1,3,3a,7-tetraazaindene-4-thiol.

10. The process of claim 1, wherein said compound is 6-phenyl-1,3,3a,7-tetraazaindene-4-thiol.

11. The process of claim 1, wherein said compound is 5-bromo-6-methyl-1,3,3a,7-tetraazaindene-4-thiol.

12. The process of claim 1, wherein said compound is 2,6-dimethyl-1,3,3a,7-tetraazaindene-4-thiol.

13. The process of claim 1, wherein said compound is S-ethyl-G-methyl-1,3,3a,7-tetraaZaindene-4-thiol.

14. The process of claim 1, wherein said compound is 5-iso-butyl-6-methyl-1,3,3a,7-tetraazaindene-4-thiol.

15. The process of claim 1, wherein said compound is 2-benzyl-6-methyl-1,3,3a,7-tetraazaindene-4-thiol.

16. The process of claim 1, wherein said compound is 2-methylthio-4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene.

17. The process of claim 1, wherein said compound is 4,6-dihydroxy-2-methylthio-1,3,3a,7-tetraazaindene.

18. The process of claim 1, wherein said compound is 4-hydroxy-2-methylthio 5,6 trimethylene-l,3,3a,7-tetraazaindene.

19. The process of claim 1, wherein said compound is 4-hydroxy 2 methylthio-5,6-tetramethylene-l,3,3a,7- tetraazaindene.

References Cited UNITED STATES PA TENTS 3,017,270 1/1962 Tregillus 9666.3 3,128,180 4/1964 Henn et al. 9695 3,335,009 8/1967 Rasch et al. 96-66.5 3,397,987 8/1968 Luckey et al. 96109 3,615,524 10/1971 Milton 96-66.3 3,622,330 11/1971 Valiaveedan 96-66.3

FOREIGN PATIENTS 295,058 7/1966 Australia 96-109 NORMAN G. TORCHIN, Primary Examiner R. L. SCHILLING, Assistant Examiner U.S. Cl. X.R. 9666.5, 109 

